Diagnosis help

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dubG

Member
Here is what is going on:
  • This is my first grow
  • 2 plants, bag seed, 2 very different strains (1 is more sativa dominant, the other more indica)
  • Plant #1 is about 5 weeks from seed and Plant #2 is about 4 weeks from seed.
  • Both plants have been under 18/6 since seed
  • ~275 actual watts of CFLs (12 x 23watts)
  • Miracle grow potting soil, 2.5 gallon pots
  • Miracle grow all purpose plant food 24-8-16, following the "indoor plant" instructions, 1/2 teaspoon per gallon of water once every 1-2 weeks
  • I water when the soil is dry at least an inch down and then I continue watering until it drips out the holes at the bottom of the pot a bit. The soil / pots drain very well.
  • I started adding 2 teaspoons of epsom salt per gallon of water roughly 1 week ago because plant #1 had a problem and using all the guides/info from the forum, to me it looked like a Mg deficiency so I tried the epsom salt suggestion and it appears to have stopped the problem from spreading after it had already spread quite a bit. I have since trimmed off the affected leaves that had dried out and died.
  • For good measure, I started giving plant #2 the epsom salts as well because I noticed that my nutes, nor my soil listed Mg as an ingredient so it made sense that there could be a deficiency
  • I thought things were going well, until now a week later plant #2 is starting to show the same signs as #1 did earlier on, and since #2 has already been getting epsom salts added to the water I'm starting to think my diagnosis of Mg deficiency is wrong and I'm turning to the experts to help before this problem takes over my plants
  • I am growing in a home built cabinet. Temps near the soil are in the low 80s. My grow space is 2x2x4=8 square feet and my 3" exhaust fan is ~35CFM and I have 2 passive 3" intakes for incoming air. Air is swapped roughly 3 times per minute in my grow space.
  • I am unsure of my exact PH. I got a cheapo "soil tester" combo ph/light/moisture meature but I'm not sure how much I trust it. It says my water that I'm putting in the soil is roughly 6.5-7 but when I put it in soil the rating is very high (8ish) so I don't think I trust its accuracy. I may look into buying a better meter.
  • I do not think its due to nute burn, since this didn't show up after I increased nutes or anything...
  • I am attaching some pictures of what plant #2 looks like right now. The brown/rust spots are starting to form. From what I know about what happened to #1, the brown will soon spread, the leaves will yellow/brown, curl up, and then dry out and die :cry:
  • This problem only affects the oldest leaves on the plant near the bottom. The new growth is healthy and unaffected.
That's all I can think of for now. Anyone have any clues? Thanks in advance for the help/suggestions
 

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D

dubG

Member
I am adding a pic of what plant #1 looked like after it had progressed into this problem about 1 week, right before I started added epsom salts to the water. I think/thought I halted this problem, so I trimmed the dead/affected leaves and so far the problem still seems to be gone... but it may be a ticking time bomb waiting to come back because at the same time I started adding epsom salts to the water for plant #2 and now week later it has started exhibiting similar symptoms that plant #1 did in the early stages.

Please help before plant #2 gets as bad as plant #1 did :-)

Thanks everyone
 

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Filthy Phil

Filthy Phil

Well-Known Member
my bet is your ph is low. I dont trust soil ph meters, i test the runoff with a liquid tester that costs ten bucks at home depot, a nursery or hydro store. Its a vial you fill with runoff, add a few drops of ph shit, watch the color. Since using this my results have been much better. My thought is your soil's ph is off. to test, add ph 7 water HALF at a time ( water half the amount, wait ten minutes, water the other half) discard all but the last of the runoff, and check that ph. Thats my thoughts.... isnt 2 tsp epson salts per gallon a lot? i dont know, but that sounds like a lot, could totally be wrong
 
D

dubG

Member
Filthy Phil said:
my bet is your ph is low. I dont trust soil ph meters, i test the runoff with a liquid tester that costs ten bucks at home depot, a nursery or hydro store. Its a vial you fill with runoff, add a few drops of ph shit, watch the color. Since using this my results have been much better. My thought is your soil's ph is off. to test, add ph 7 water HALF at a time ( water half the amount, wait ten minutes, water the other half) discard all but the last of the runoff, and check that ph. Thats my thoughts.... isnt 2 tsp epson salts per gallon a lot? i dont know, but that sounds like a lot, could totally be wrong
Click to expand...
My gut is telling me PH as well, especially since I have read that too high/low can look/sound just like an Mg deficiency.

I've read multiple sources saying either 2tsp to 1 tablespoon per gallon. 1 tablespoon = 3tsp, I err'd on the side of caution and gave it 2tsp

Anyone have any suggestions for a reliable / easy to use digital PH tester?
 
D

dubG

Member
weedsLV said:
When u water r u gettin the leafs wet with nutes? May b nute burn.??
Click to expand...
I have foliar fed with just water + epsom salts (it was recommended to do this for Mg deficiency and I read it should not hurt a plant without an Mg deficiency), but not with nutes.
 
D

dubG

Member
Plant 2, top down, to show where the plant is affected. As you can see it's the oldest leaves on the lower sides showing the problem. New growth remains unaffected and looks healthy.

Each day it gets slightly worse
 

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